Drawbenches



July 1959 P. s. E. Fl QEDRlKSSON 7 DRAWBENCHES 3 Sheets-Sheet '1 Filed D60. 8, 1954 y 21, 1959 P. s. E. FREDRIKSSON 2,895,597

- DRAWBENCHES I Filed Dec. 8, 1954 I s Sheets-Sheet 2 y 1959 P. s. E. FREDRIKSSON 2,395,597

DRAWBENCHES Filed Dec. 8. 1954 3 Sheets-Sheet 3 United States Patent Q DRAWBENCHES Per Sven Engelhrekt Fredriksson,-Vasteras, Sweden, as-

signor to Aktiebolaget Svenska Metallverken, Vasteras, ,Sweden, a joint stock company limited Application December 8,1954, Serial"-No:;4-l3,948 Claims priority, application sweden December 12,1953

3 Claims (Cl; 205-3) The present invention relates to improvements insdrawbench apparatus ofthe kindhavingstationary drawing dies and a 'movable carriage adapted to dravvpipe or rod blanks through said dies to reduce saidblanks'totheir transversal dimensions.

In a general aspect, an object of theinvention-is-to provide a methodof safely connecting the ends ofatleast two pipe or rod blanks to. the drawing carriage and-to maintainsaid connection throughout-the entire drawing operation.

A further object of the invention is to provide a method for releasing the drawn pipes or rods from thecarriage.

A further-object of the-invention is toprovide animproved drawing carriage, Which-willcontribute to secure a safe grip of at least two blank ends so as to prevent onintended release of: any one of said blanks-during the drawing operation, thus avoiding the-necessity-of' returning the carriage, after havingfinished the drawing ofthe rest of the blanks, for regrippingsaid released blank-and separately completing the drawing'thereof.

A further object of the invention is to-provide-a jawrneans'system actuable from a common source of power.

A further object of the inventionis to ,provide'ajaw- .means system actuable by compressed air.

A further object of the invention is to providevalve means for establishing or interrupting connection between a jaw-means actuating device and a source of compressed air in response to the displacement of the drawing carriage in relation to the dies.

Further objects and features ofthe invention will be evident from the following description of an embodiment of the invention diagrammatically shown in the accompanying drawings, wherein:

Figure 1 is a plan View of anembodiment ofthe drawing carriage according to the, invention showing, its relationship to a number of drawing dies. out of-whichthe ends of pipeor rod 'blanksextend. I

Figure 2 is a longitudinal sectionalong the line lIIl in Figure 1.

Figure 3 is a View of the drawing carriage seenin the direction of the arrow A in Figure 1.

Figure 4 is a longitudinal sectionof an air distributing arrangement for the drawing carriage.

Figure 5 is a cross sectional view substantially along the line VV in Figure 1.

Figure 6 is a crosssectionsubstantially alongtheline Vl-Vlin Figure 3.

In the drawings 1 is a drawing carriageand 2 a support for a number of drawing dies 3 stationarily arranged in spaced relation to the drawing carriage 1. Through thedrawing dies, which in'the embodiment shown are three in number, the preformed ends 4 of three rod or pipe blanks 5 extend.

The drawing carriage 1 which is movable in relation to the drawing dies 3, is supported by four Wheels 6, rotatably mounted on shafts 7 fixed to the drawing carriage 1 in any suitable way. The wheels 6 runon rails 6a (Figure 3). Furthermore the drawing carriage is 2,895,597 I Patented July-121, :1959

guided horizontally by a number of wheels 9 rotatably -mounted on vertical shafts 8- and adapted to roll in pairs r zagainstlateral flanges on the rails 6a.

Located on opposite sides'of the drawing carriage are forked members lit-and 11 hingedly connected to the drawing carriage by meansof pins 12 and'13; 'At its front end each fork 10, 11' has holes '14 and 15,-.respectively, for the attachment of one end of a chain, not

'-.shown, by means of a pin or the like. Each chain is passed over a sprocket 'wheel suitably placed adjacent to x the drawing dies and a further sprocket wheel'placed at theopposite'end of the drawbench in relation to the. dies,

: the other end of the chain'being attached to the two ends J ofa'two armed lever-such=as a yoke pivotally mounted by-rneans of a pin to two lugs or the like 16 provided-with holes 16a. A pair of the sprocket wheels may be connected to a driving motor by'means of which the drawing 1 carriage can be moved'toward or away from the drawing dies.

:Rigidly attached to theframe 17 of the drawing car- ..riage-l is ablock 17a made from-steel or; similar material which carries three pairs of drawing jaws 13; To

this end the block 17a is provided with recesses 1.9,- each "of which presentstwo vertical planes or wallslti'diverging in the direction in which the drawing carriage is moved during the proper drawing operation. Each recess 19 has a wedge 21, the sides 22 of which are substantially in *parallel to the planes 20. One vertical plane 23 of each jaw '18 engages one'wall 20 of the associated recessand the jaws are movable in either direction along said walls. The jaws are retained in the block 17a by means of-plates 20a fastened to the same from below. At its top each jaw 18 presents a flange-like guide member 25, which is an .gageable to one side 22 of the wedge 21, so that each guide member 25 with its jaw 18 may be-displaced between a wall 20 and a side 22, while advancing or removing the gripping surfaces 24 of each pair of jawsl tosand from each other respectively. Each guide member 25 is provided with an elongated groove 26a, into which latch means comprising a pin 27 (Figure 6) depends for a purpose which will be explained later on. The gripping 7 surfaces 24 may be provided with serrations or the-like for frictional engagement with the pipe or rod ends.

-With reference to Figures 1 and Z-three forked members comprising the hubs 29 and arms 31 are 'pivotally sup- 1 ported on a common shaft 28 which is fixedly attached to the frame 17, said forked members being best illustrated in Figure 2, wherein 29 designates a hub or sleeve, from which extends a lever 30 fixedly attached thereto. Extending from each sleeve 29 are two arcuate arms -31 fixed thereto intohorizontallyspaced relation to each other.

\ spring 34 abuts, the other end of saidgspring engaging a -plate-36 to which two pins 35 are attached for guidingthe pair of springs 34. The plate 36 is carried by a bolt-37 screwed into the block 17a.

The lever 30 by means of a pin 38 is hingedly connected to the outer forked end of a piston rod 40,

which is normally retained in the position shown in Figure 2 by means of a compression spring 41, one end of which rests against an annular flange 42 of a sleeve member 43 attached to the piston rod-40 and the; other end of which engages the head 44 of a piston cylinder generally designated by 45, in which apiston, not shown,

is adapted to move longitudinally. The-piston cylinder by means of the pivot pin is hingedly connected=to a lug 47 projecting from the frame 17, so that the cylinder 3 45 with the piston and the piston rod 40 may be pivoted within certain limits.

The piston, not shown is assumed, in the general relationship of the details as shown, in Figure 2, to be located substantially adjacent to the cylinder head 44 and is urged downwardly in the piston cylinder 45 toward the pivot 46 by means of compressed air or the like, each piston cylinder 45 being provided with a flexible supply tube 48 extending to one side of the drawing carriage as shown in Figure 1. With its outer end each of said tubes 48 is directly connected to a sleeve 49 shown in longitudinal section in Figure 4. The flexible tubes 48 communicate with the inside 50 of the sleeve 49 through ports 51.

Fixed to the sleeve 49 by means of bolts 52 is a plate 53, which at its free end shows an oblique cam surface 54, the purpose of which will be explained later on.

In the position occupied by the drawing carriage in Figure 1 the interior of the cylinders 45 communicate by means of tubes 48 and the interior of the sleeve 49 directly with the atmosphere, the pistons in the cylinders 45 being retained in their ineffective positions shown, by means of the springs 41, and the members 31 being retained in their initial positions. As indicated above, the piston system is actuable by means of compressed air controlled by a particular valve arrangement shown in Figure l and comprising a valve housing 55 with a valve of any convenient kind. Such valve is normally retained in closed position but may be operated from the outside of the valve housing by means of a piston 56, which opens the valve when pressed into the valve housing. The piston 56 at its top end carries a roller or the like 58 mounted for rotation about a pivot 57. Furthermore the valve housing 55 is provided with a supply conduit 59 and a discharge conduit 60 for compressed air. Through a fitting 61 the conduit 60 is connected to an elongated nozzle 62, which is extended at its front end to form a head 63 provided with a peripheral groove 64, in which a sealing ring of any suitable kind is fitted. The nozzle 62 by means of resilient members, that is, rubber pads 65, is flexibly supported in a head 66, which by means of a bracket 67 is fixedly attached to the valve housing 55. The entire valve arrangement including the nozzle 62 is stationarily mounted and may suitably be placed in the vicinity of the drawing dies but may also be placed at another point suitable for its operation.

The drawing carriage according to the invention operates in the following manner:

When, with reference to Figure l, the drawing carriage is to be used for drawing the pipe or rod blanks through the drawing dies 3 it is moved by means of the chains and motor toward the pipe or rod ends 4 extending from the drawing dies 3, the drawing jaws 18 being in their opened position. As the drawing carriage is approaching the pipe ends 4 the head 63 of the nozzle 62 enters the interior of the sleeve 49 shown in Figure 4. Said sleeve, as shown, at its front end is somewhat bevelled to guide the head 63 smoothly into the sleeve 49. By means of the rubber pads 65 the head 63 can perform a small motion to be guided in a suitable position into the interior of the sleeve so that the sealing 64 on the head 63 engages the cylinder wall of the sleeve 49. When the head has moved a certain distance within the sleeve 49, the cam surface 54 on the plate 53 will engage the roller 58 which urges the slide 56 into the valve housing 55, whereupon the valve will open the communication between the supply conduit 59 and the discharge conduit 60. A super-pressure is then created in front of the pistons of the cylinders 45 by means of the nozzle 62, the head 63, the sleeve 49 and the conduits 48 to move said pistons downwardly toward their bottom positions against the pressure of the successively compressed springs 41. The movement of the piston rods 40 into the cylinders 45 causes the arms 30, 31 and 32 to be pivoted against the position shown in dot and dash lines in Figure 2. Said position is the extreme position into which the arms can be pivoted, the actual degree of movement depending upon the transversal dimensions of the pipe or rod ends 4. In said motion the arms 31 will abut against the rear ends of the jaws 18, to urge those to the left, as shown in Figure 2, in their wedge guides toward each other while positively engaging the ends 4. Simultaneously with said movement and before the arms abut against the jaws the pins or latch means 27 are lifted (see Figure 6) entirely out of the grooves 26a in the plates 25 of the jaws to enable the jaws to move freely in the guides. At this moment the grip between the jaws and the pipe or rod ends has not the desired strength. The drawing carriage is then put in motion, which will cause the wedge guides to move further toward each other to positively secure the desired grip of the jaws on the pipe or rod ends. During said first moment of the movement of the carriage the sleeve 49 on the drawing carriage leaves the nozzle parts 62, 63, 64 so that the pneumatic pistons and piston rods 40 by means of the springs 41 are returned to their initial positions shown in Figure 2. Simultaneously therewith the arms 31 on the forked members swing back to their initial positions in the particular pockets in the frame 17a as shown in Figure 6. The arms 32 are also swung downwardly to cause the springs 34 to urge the pins or latch means 27 downwardly into engagement with the jaws 18. It will be understood that the elongated grooves 26a of said jaws during the engagement with the pipe or rod ends 4 have moved forwardly in the wedge guides to such an extent that the pins or latch means 27 will rest directly against the upper surface of said jaws and remain in such position during the entire drawing operation. When finally the pipes or rods at the end of the drawing operation are released from the drawing dies 3, the release of the tension maintained during the drawing operation on the pipes or rods contributes to impart to the latter a vigorous movement in the drawing direction to cause each pair of jaws 18 to be urged to the right, as shown in Figure 2, in the wedge guides to be spaced apart, the jaws and the pipe or rod ends 4 being disengaged. The drawn pipes or rods continue their motion forwardly below the drawing carriage, the ends 4 being guided by the sloping plate shown in Figure 2. The pipes or rods are then permitted to fall upon a suitable bed. At the end of their spacing movement the jaws 18 abut against particular abutments as is evident from Figure 6. During said motion of the jaws the grooves 26a therein will pass beyond the pins or latch means 27, which during this operation will snap down into the grooves thus preventing the jaws from rebounding.

The invention is not limited to the embodiment shown and described but may be varied in several respects within the scope of the basic inventive idea.

Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. Apparatus for drawing a plurality of elongated members through drawing dies, said apparatus comprising a drawing carriage, a plurality of drawing dies, said carriage having an open ended recess disposed in axial alignment with each die to provide an unobstructed path of movement for said members after leaving said dies, a pair of member gripping wedge jaws slidably disposed in each recess, means for limiting sliding movement of said jaws in one direction, individual means for moving each pair of jaws into gripping engagement with the associated member, separate pneumatic means for actuating each individual means, means for supplying pneumatic pressure to said pneumatic means from a common source whereby the force urging each pair of jaws into gripping engagement with said members will be equal irrespective Oi differences in cross sectional size or shape of said members and means for retracting said individual means out of the path of movement of said jaws in said one direction.

2. Apparatus as defined in claim 1 in which automati cally operable latch means engageable with said jaws is provided for preventing inadvertent re-engagement of said jaws with said members after completion of the drawing operation, said latch means comprising spring loaded slidable pins and recesses in said jaws for receiving said pins upon disengagement of said jaws from said members.

3. Apparatus as defined in claim 2 in which said pneumatic means is provided with latch pin engaging means to disengage said pins from said recesses upon actuation of said pneumatic means to move said jaws into ping engagement with said members.

References Cited in the file of this patent UNITED STATES PATENTS Howard Oct. 19, Scoville Aug. 27, Harpster Feb. 22, Hunt Mar. 17, Kerr July 16,

FOREIGN PATENTS Great Britain Dec. 5, France Oct. 22, 

